Despite decades of research, we still have poor understanding of the global and regional carbon cycle, and with significant uncertainty on how the carbon cycle is responding to climate change. Is it then any wonder that the world’s governments continue to drag their feet on fossil fuel emissions mitigation (despite rhetoric to the contrary). Currently, the natural land and ocean carbon sinks give humanity a “free ticket”, in that they are absorbing roughly half of the CO2 we emit into the atmosphere, greatly reducing the severity of climate change. But for how long?

Atmospheric oxygen (O2) is consumed at the same time that fossil fuels emit CO2 ; conversely, atmospheric O2 is emitted at the same time that land plants grow and absorb CO2 . But ocean processes do not exhibit the same anti-correlation between CO2 and O2 fluxes. These couplings and decouplings between CO2 and O2 result in O2 being a powerful atmospheric tracer, providing new insights into the carbon cycle. In this seminar, I will highlight some exciting applications of atmospheric O2 measurements, including: O2 from BAS ’s Halley Research Station, verification of fossil fuel CO2 emissions, quantifying carbon sinks, O2 in terrestrial ecology, and O2 in China